1. Field of Invention
The present invention relates to a diamond disc manufacturing process, and more particularly to a diamond disc manufacturing process which can provide uniform distribution and orientation of diamond particles.
2. Related Art
In recent years, since the technology of integrated circuits (IC) is developed rapidly and becomes mature, the semiconductor industry becomes one of the vigorously developed industries. Semiconductor products may be widely used in information, communication, consumer electronics, industrial instruments, transportation, defense and space, and other fields, and have great impacts on electronic products. Therefore, the semiconductor products certainly are of great importance.
Silicon wafer is a quite important material in the semiconductor industry. The silicon wafer must be subject to a chemical mechanical polishing (CMP) process. Firstly, planarzing the wafer surface, so that subsequent processes for manufacturing chip may be performed thereon, thereby enhancing the accuracy and yield of the process. The efficiency of a polishing pad used in the CMP process for a long time will be gradually reduced since abrasive particles may be filled in the clearance of the polishing pad. Thus, the polishing pad must be conditioned regularly to remove residual impurities and polishing remains, so as to maintain an optimal polishing state. Therefore, the semiconductor industry applies the diamond to a diamond disc (pad conditioner) for cleaning the polishing pad. The diamond disc (pad conditioner) is disc-shaped or ring-shaped and is also referred to as a diamond disc (pad conditioner).
The method of manufacturing a diamond disc in the prior art includes forming a metal bonding layer by a electroplating or sintering process, so as to wrap diamond particles and stick them on a surface of a metal substrate. However, the two conventional methods of manufacturing a diamond disc cannot provide a sufficient bonding power to stick the diamond particles on the surface of the metal substrate closely. Thus, the diamond particles may drop off from the diamond disc (pad conditioner) due to the insufficient bonding power. In a CMP process, the dropped diamond particles easily scratch the expensive silicon wafer, leading to the damage to the surface of the silicon wafer. In order to solve the problem that the diamond particles easily dropping off, a brazing process must be added, but that will cause an increase of the manufacturing processes and cost.
In addition, in order to extend the lifetime of the diamond disc (pad conditioner) and improve the polishing characteristics. Taiwan Patent No. 412461 and U.S. Pat. No. 5,092,910 disclose a die hole or a screen with regularly distributed holes is used to make the diamond particles arranged on an abrasive tool in a pattern regularly and a manufacturing method thereof, which replaces the manner of arranging the diamond particles randomly and irregularly on the conventional polishing tool. Furthermore, Taiwan Patent No. 541226 discloses a method of uniformly arranging diamond particles to have the same height. The method arranges the polishing particles on a positioning trench on a carrier with an appropriate interval, and fills the bonding agent in the positioning trench to achieve the uniform orientation of the polishing particles.
Although Taiwan Patent No. 412461 and U.S. Pat. No. 5,092,910 may achieve the purpose of uniformly arranging the diamond particles with an appropriate interval. However, since the meshes of the adopted die hole or the screen have a size larger than that of the diamond particles, the diamond particles just only arranged regularly according to the positions of the meshes, but the orientation of each of the diamond particles in the arrangement position cannot be controlled, resulting in that the diamonds on the diamond disc (pad conditioner) have different heights, which negatively influences the polishing uniformity and lifetime of the diamond disc (pad conditioner). Furthermore, after the diamond particles stick and are arranged on the surface of the wafer, a brazing process is still reburied to be closely bond the diamond particles with the surface of the wafer, thereby causing the problems, such as deformation of the substrate and deterioration of the diamond particles.
In Taiwan Patent No. 541226, the carrier for arranging the diamond particles must be milled firstly into a positioning trench with a predetermined shape, which results in the increase of the manufacturing cost due to the additional processing procedure of the carrier. Furthermore, in order to make the diamond particles have uniform orientation, it is required to spend more manufacturing time on the procedure of placing the diamond particles, thus reducing the efficiency of manufacturing the diamond disc (pad conditioner).
In the conventional method of manufacturing the diamond disc (pad conditioner) although the plurality of diamond particles may be arranged regularly and uniformly, the diamond particles cannot have uniform orientation, or more manufacturing cost and time must be spent to achieve the purpose of arranging the polishing particles in uniform orientation.